Kingdom Hearts is the first appearance of "emo" Cloud. It fit for the game because he was in the game as a boss battle, a servant of hades, which made for a fun fight. After you beat him though, obviously they were not going to leave him as just a bad guy, so he has a talk with Sora about how he had a struggle against his inner darkness, fitting the kingdom hearts theme. (Not to mention he stole Vincent's cape, glove, and wing. Wtf?)
The problem is that Square Enix just rolled with it and put "emo" cloud back into main entries in the series, starting with Advent Children. Even though Cloud's emoness is explained in the movie, and that he had deep guilt and regret for not being able to save either Aerith or Zax from dying, he had already reconciled those feelings when Tifa was f*cking around in his subconscious mind. After Cloud recovered, he was back to his former self, which was a likable, witty, arrogant, flirtatious hero. It didn't make sense for him to relapse back into those feelings, and so he was rejected by people who grew up liking the original game and was adopted by those weird anime cosplayers who swear Kingdom Hearts' story is really good and not at all convoluted. (I actually like Kingdom Hearts somewhat, but I feel like it's got to the point of ridiculous.)
Every entry Cloud was ever featured in from then on out was emo, and so the real cloud faded into myth and legend among older gamers. Now one of the main reasons FF7 is bashed is because of its spinoffs' representation of Cloud.
But it all goes back to two simple points for me: One, Square Enix could make the game with slightly updated graphics and keep everything the same. I know some people would be upset it would be the same, but not many, and the game would sell like crazy. It wouldn't even take much cost at all if they made it as a handheld game of some sort. Two, even if they did f*ck it up at least people would finally stop talking and asking for it, and it wouldn't affect those who still play the original.